The blocks I use for the outhaul are "micro" sized, i.e. about the smallest that are made.
K.C., I'm not fully sure I'm picturing your suggested setup....
The cleat I have is not very distinct in the picture. This one releases when the line is pulled away from the mounting surface. What's shown in the picture is a released cleat where just the stopper knot is holding. This was taken a few feet out of the dock before the first of us realized the outhaul hadn't been tightened.
There are V cleats that engage when you pull away from the mounting surface. Those are easier to "set" in my experience. The one I have wants to be pulled (under load) perfectly parallel to the boom and then allowed to "set" while not deviating from that position. Any deflection and it won't grab the line.
On another boat I sail, some of the cleats are this style:
Ronstan V-Jammerand while I haven't tried it for the outhaul such a cleat would seem to be easier to set, so that if you plan to "snug" the outhaul, you can do it with a quick tug...
Actually, now that I re-read your description your "upgrade" would use the block to align the pull along the boom. So the line, coming from the sail is fed first through the cleat, continues, goes through the block and ends in a stopper knot. I can picture that. Also has the advantage of allowing anyone who can grip any part of the line between cleat and block to operate the outhaul. Brilliant. As it would cost just the same as replacing the cleat, I'll have to seriously think about it.
About your cascade - my experience is that I don't need that, but if I was routinely sailing in heavier winds, I could see how that would benefit.